A study was designed to establish

Answer choices

1. A

   No Impact6% picked this

   Commercially important fish depend on sea-bottom animals for much of their food, so a drop in catches of those fish would be

   This tells us about a possible metric for measuring damage to sea-bottom communities, but we don't have any data about whether there has been any drop in catches of certain fish, so we have no way to use this metric to judge the current situation near oil rigs.

   6%
2. B

   Correct72% picked this

   The discharge of oil from offshore oil rigs typically occurs at the surface of the water, and currents often carry the oil considerable distances

   Why this is right

   This hurts the argument by telling us that the study was looking in the wrong place. If we're trying to judge the impact of oil rigs, we shouldn't be looking near the rigs as the study did. We should be looking at considerable distance from the rig, because that's where the discharge would settle and so that's where the potential damage would occur. This answer doesn't offer any positive evidence that damage is occurring, but it weakens the argument by saying that the evidence presented is pretty much irrelevant to the conclusion being drawn.

   Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

   72%
3. C

   No Impact18% picked this

   Contamination of the ocean floor from sewage and industrial effluent does not result in the destruction of all sea-bottom animals but instead reduces species

   If the premise had said something like, "There are still plenty of animals near the rigs, so there wasn't any adverse affect", then maybe we could weaken by saying, "Yo, you can't just measure whether there are plenty of animals. We're not saying adverse effects would look like a total lack of animals. It would look like less species diversity and less density of life." But the premise was just saying "the community near the rigs (in terms of number, diversity, density) looked very similar to the community near the control sites".

   18%
4. D

   Strengthens, if Anything2% picked this

   Only part of any oil discharged into the ocean reaches the ocean floor: some oil evaporates, and some remains in

   This is a pretty weak, wishy-washy idea. But if anything it is minimizing the potential risk of oil discharge to sea-bottom communities by saying that some of the discharge never reaches the ocean floor.

   2%
5. E

   Irrelevant Distinction1% picked this

   Where the ocean floor consists of soft sediment, contaminating oil persists much longer than where the

   We have no idea if the ocean floor near the rigs or near the control sites has soft vs. rocky sediment, so even if this distinction were interesting to us, we have no way to apply it to the situation at hand.

   1%